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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Síntese de compostos α-amino-1,3-dicarbonílicos em microrreator de fluxo contínuo e suas aplicações / Synthesis of α-amino-1,3-dicarbonyl compounds in continuous flow micro-reactor and their applications.

Evelin Fornari Pereira 19 May 2017 (has links)
Na primeira parte deste trabalho apresentamos uma forma eficiente para sintetizar quinze novos compostos α-amino-1,3-dicarbonílicos através da reação multicomponente de Ugi. Para estas sínteses foi utilizado o microrreator de fluxo contínuo, um aparelho que possibilita uma excelente transferência de calor, de massa e alta relação superfície / volume. Algumas das vantagens em se utilizar um microrreator de fluxo contínuo na síntese são: redução do tempo de reação, aumento de rendimento, seletividade das reações e menor geração de resíduos. Foi possível assim estudar as reações químicas em condições inéditas, variando parâmetros como: temperatura, pressão, tempo de residência e relação estequiométrica. Um comparativo de rendimento da síntese de quatro moléculas foi realizado e pôde-se notar a eficiência do equipamento utilizado, pois os rendimentos obtidos foram superiores quando as mesmas moléculas foram sintetizadas através da reação one-pot. Um scale-up da reação de Ugi também foi realizado e apresentou um resultado satisfatório. Na segunda parte alguns destes compostos foram utilizados como intermediários na formação de uma ligação amídica e também aplicamos a metodologia relacionada à cicloadição catalisada por cobre entre alquinos e azidas na síntese de cinco novos compostos 1,2,3-triazóis. Este foi o primeiro trabalho realizado no Laboratório de Compostos Heterocíclicos da Faculdade de Ciências Farmacêuticas utilizando o microrreator de fluxo contínuo e este equipamento atendeu as necessidades deste trabalho com efetividade. / The first part of this work we present an efficient way to synthesize fifteen new α-amino-1,3-dicarbonyl compounds through the multicomponent Ugi reaction. For these syntheses was used the continuous flow micro-reactor, an equipment that allows an excellent transfer of heat, mass and high surface / volume ratio. Some of the advantages of using a continuous flow micro-reactor in the synthesis are: reduction of reaction time, increase of yield, selectivity of reactions and less generation of residues. It was possible to study the chemical reactions under new conditions, varying parameters such as: temperature, pressure, residence time and stoichiometric ratio. A yield comparison of the synthesis of four molecules was carried out and it was possible to note the efficiency of the equipment used, because the obtained yields were superior when the same molecules were synthesized through the one-pot reaction. A scale-up of the Ugi reaction was also performed and presented a satisfactory result. In the second part some of these compounds were used as intermediates in the formation of an amide bond and we also apply the methodology related to the copper catalyzed cycloaddition between alkynes and azides in the synthesis of five new 1,2,3-triazoles compounds. It was the first work performed in the Laboratory of Heterocyclic Compounds of the Faculty of Pharmaceutical Sciences using the continuous flow micro-reactor and this equipment met the needs of this work with effectiveness.
12

Síntese e avaliação antiparasitária de quinolinas conjugadas à 1,2,3-triazóis

Meinel, Raíssa Soares 22 July 2016 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-04T14:25:19Z No. of bitstreams: 1 raissasoaresmeinel.pdf: 3680186 bytes, checksum: ec85e901c8bb646178cf7aa00e18cdd6 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-13T13:49:00Z (GMT) No. of bitstreams: 1 raissasoaresmeinel.pdf: 3680186 bytes, checksum: ec85e901c8bb646178cf7aa00e18cdd6 (MD5) / Made available in DSpace on 2017-05-13T13:49:00Z (GMT). No. of bitstreams: 1 raissasoaresmeinel.pdf: 3680186 bytes, checksum: ec85e901c8bb646178cf7aa00e18cdd6 (MD5) Previous issue date: 2016-07-22 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A presente dissertação, intitulada "Síntese e Avaliação Antiparasitária de Quinolinas Conjugadas à 1,2,3-Triazóis” trata da preparação, caracterização e avaliação biológica de compostos orgânicos contendo uma porção quinolínica associada a um anel triazólico 1,4-dissubstituído. Explorando a ferramenta de hibridação molecular, encontra-se descrita também neste trabalho a preparação de Bases de Schiff a partir das quinolinas conjugadas. Os compostos foram preparados através da formação de triazóis utilizando a reação do tipo “click” chemistry. As estruturas químicas dos produtos obtidos foram confirmadas por espectroscopia no infravermelho, ressonância magnética nuclear de 1H e de 13C e faixa de fusão. Os compostos sintetizados foram avaliados em crescimentos de parasitos in vitro e in vivo (P. berghei e leishmania). / The dissertation entitled “Synthesis and antiparasitic evaluation of Quinolines conjugated 1,2,3- Triazoles” deals with the preparation, characterization and evaluation of the biological potential of organic compounds containing a quinoline portion associated with 1,2,3-Triazole 1,4-dissubstituted. Further exploring the molecular hybridization tool is also described the preparation of Schiff bases from these conjugated quinolines. The compounds were prepared by using the triazole forming reaction such as "click " chemistry . The chemical structures of the products obtained were confirmed by infrared spectroscopy , nuclear magnetic resonance 1H and 13C and melting point . The synthesized compounds were evaluated in growth of parasites in vitro and in vivo (P. berghei and leishmania).
13

Synthesis and Characterization of Polydentate C3 Symmetric Ligand Systems in Metal Coordination

Stollberg, Peter 10 August 2018 (has links)
No description available.
14

Síntese de 5-organoteluro-1H-1,2,3-triazóis-1,4-dissubstituídos, funcionalização via reação de acoplamento cruzado de Sonogashira e síntese one-pot de derivados do indol-3-glioxila e indol-3-glioxil-1,2,3-triazóis / Synthesis of 5-organoteluro-1,4-disubstituted-1H-1,2,3- triazoles, functionalization via Sonogashira cross-coupling reaction and synthesis one-pot of indole-3-glyoxyl derivatives and indole-3-glyoxyl triazoles

Vasconcelos, Stanley Nunes Siqueira 27 September 2013 (has links)
No capítulo 1 apresentamos uma síntese eficiente de compostos 5-organoteluro-1H- 1,2,3-triazóis realizada via reação de cicloadição [3+2] entre azidas orgânicas e alquinos substituídos com organotelúrio. Além disso, os 5-organoteluro-1H-1,2,3-triazóis foram funcionalizados na posição 5 do anel triazólico por reação de acoplamento cruzado de Sonogashira. A regioquímica dos produtos de cicloadição foram descritas com base em experimentos de RMN, cálculos teóricos e cristalografia de raio-x. Apresentamos uma proposta mecanística para a cicloadição mediada por cobre, baseada em experimentos de espectrometria de massas de alta resolução. No capítulo 2, investigamos a eficiência de reações one-pot com indol, cloreto de oxalila e diferentes nucleófilos para obtermos derivados do indol-3-glioxila em condições adequadas. Do mesmo modo, envolvendo a adição de azidas orgânicas, levando à síntese de indol-3-glioxil-1,2,3-triazóis, os produtos foram obtidos com rendimentos que variaram de 59 a 85%. / In chapter 1 we present an efficient synthesis of 5-organotelluro-1H-1,2,3-triazole compounds that was accomplished via the [3+2]-cycloaddition reaction of organoazides and organotelluro alkynes. Additionally, 5-organotelluro-1H-1,2,3-triazoles were readily functionalized at the 5-position via the Sonogashira cross-coupling reaction, leading to highly functionalised triazoles. The regiochemistry of the products was assessed by bidimensional NMR experiments, theoretical calculations and x-ray crystallography. We presented a mechanistic proposal for the cycloaddition mediated by copper, based on high resolution mass spectrometry experiments. In chapter 2 we investigated a general and efficient reaction of indole with oxalyl chloride and nucleophiles providing indole-3-glyoxyl derivatives which has been developed in mild conditions. In the same fashion, the other reaction involved the addition of organic azides leading to the synthesis of indole-3-glyoxyl-1,2,3-triazoles, which proceeds smoothly generating the products in moderate to high yields.
15

Conception et synthèse de ligands peptidomimétiques du récepteur de la ghréline / Design and synthesis of peptidomimetic ligands of ghrelin receptor

Maingot, Mathieu 18 November 2015 (has links)
La ghréline est une hormone de 28 acides aminés, synthétisée principalement par l'estomac. D'abord identifiée comme un sécretagogue de l'hormone de croissance, elle joue également un rôle central dans la prise alimentaire, la glycémie ainsi que dans certains processus liés à l'addiction. Ces effets sont médiés par un récepteur couplé aux protéines G : le GHS-R1a (Growth Hormone Secretagogue Receptor). Ce récepteur possède une activité constitutive élevée et un réseau de signalisation intra-cellulaire relativement complexe via l'activation de β-arrestines et de différentes isoformes de protéines G (Gq, Gi/o, G12/13). Compte tenu de ces multiples effets, les ligands du GHS-R1a présentent un intérêt thérapeutique certain.Cette thèse est consacrée au développement d'antagonistes et d'agonistes inverses du hGHS-R1a, dont la structure est basée sur le motif 1,2,4-triazole 3,4,5-trisubstitué. Grâce à une étude successive des différents substituants de cette plateforme peptido-mimétique nous avons identifié des antagonistes d'affinités nanomolaires ainsi que des agonistes inverses possédant une efficacité significative. Ces composés paraissent donc être des candidats intéressants pour des études in vivo sur des modèles de prise alimentaire ou d'addiction. D'autre part, une étude pharmacologique sophistiquée, menée sur nos composés, a démontré qu'il est possible d'obtenir des ligands biaisés sur la base du motif triazole. Ces résultats fournissent de nouvelles informations sur la sélectivité fonctionnelle du GHS-R1a. Ainsi, associés à des études in vivo complémentaires, ces données pourraient être précieuses pour la conception de nouveaux médicaments possédant des effets secondaires limités. / Ghrelin is a hormone of 28 amino acids, mostly synthesized in the stomach. Firstly identified as a growth hormone secretagogue, this peptide is also involved in food intake, blood glucose and in some processes related to addiction. Ghrelin effects are mediated by a G protein-coupled receptor: GHS-R1a (Growth Hormone Secretagogue Receptor). This receptor has a high constitutive activity and a complex intra-cellular signaling network via the activation of β-arrestin and different isoforms of G protein (Gq, Gi / o, G12 / 13). Given these multiple effects, ligands of GHS-R1a have a therapeutic interest.This thesis is devoted to the development of antagonists and inverse agonists of hGHS-R1a whose structure is based on the 3,4,5-trisubstituted 1,2,4-triazole scaffold. Thanks to a successive study of the various substituents of the peptidomimetic platform we identified antagonists with nanomolar affinity and inverse agonists with a significant efficiency. These compounds appear to be attractive candidates for in vivo studies on food intake or addiction models. On the other hand, a sophisticated pharmacological study, conducted on our compounds, has demonstrated that it is possible to obtain biased ligands based on the triazole motif. These results provide new informations about the functional selectivity of GHS-R1a. Thus, these data, combined with additional in vivo studies, could be useful for the design of new drugs with limited side effects.
16

Uso de paclobutrazol em tomateiro cultivado em dois ambientes /

Silva, Katiane Santiago. January 2008 (has links)
Orientador: Max José de Araújo Faria Júnior / Banca: Shizuo Seno / Banca: José Luis Susumu Sasaki / Banca: Rerison Catarino da Hora / Banca: Humberto Silva Santos / Resumo: O trabalho teve por objetivo avaliar o efeito da aplicação de diferentes concentrações (0; 50; 100 e 150 mg L-1) de paclobutrazol (PBZ) na produção de mudas, no crescimento, desenvolvimento de plantas, na produção e na qualidade físico-química de dois híbridos de tomateiro (Jennifer e AF 7631), em campo aberto e em ambiente protegido. O trabalho foi desenvolvido de abril a outubro de 2007, na UNESP - Campus de Ilha Solteira, Estado de São Paulo. O PBZ foi aplicado às mudas, aos 15 dias após a germinação. Para avaliação das mudas, foi utilizado delineamento inteiramente casualizado, em esquema fatorial, com 4 repetições e 10 plântulas por parcela. Para avaliação do desenvolvimento e produtividade dos híbridos após transplante, adotou-se o delineamento em blocos casualizados, em esquema fatorial, com análise para grupo de experimentos, modelo fixo, com 4 blocos por ambiente e 9 plantas por parcela. O uso de concentrações crescentes de paclobutrazol reduziu a taxa de crescimento e a altura de plantas, aumentou o diâmetro da haste, reduziu a brotação lateral e reduziu a produtividade da cultura. O PBZ também influenciou significativamente na massa de seca de parte aérea, com aumento linear na massa seca da parte radicular. O híbrido Jennifer apresentou maiores taxas de crescimento absoluto, resultando em plantas com maior altura que o AF 7631, sem que houvesse diferenças entre eles, no que se refere ao diâmetro da haste, brotação lateral e produtividade. Em ambiente protegido, foram obtidas plantas mais vigorosas, com maior altura, brotação lateral e maior produtividade que em campo aberto. O ambiente de cultivo não interferiu em nenhuma das características qualitativas avaliadas, para o híbrido AF 7631, enquanto que, para o Jennifer houve efeito significativo do ambientes de cultivo sobre o teor de sólidos solúveis e acidez titulável... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to evaluate the effect of different concentrations (0, 50, 100 and 150 mg L-1) of paclobutrazol (PBZ) on the production of seedlings, plant growth, development, plant yield and physico-chemical quality of fruits, of two tomato hybrids (Jennifer and AF 7631), cultivated in open field and in protected environment. The work was conducted from April to October of 2007, at UNESP - Campus of Ilha Solteira, Sao Paulo State. The PBZ was applied to seedlings, at 15 days after germination. For evaluation of the seedlings, the used statistical experimental design was completely randomized, in factorial outline, with 4 repetitions and 10 seedlings per plot. For evaluation of the development and productivity of two hybrids after transplant it was used a randomized block design, in a factorial array, with analysis for group of experiments, in a fixed model, with 4 replications for environment and 9 plants per plot. The use of increasing concentrations of paclobutrazol reduced the height of plants and their growth rate, increased the stem diameter, decreased the side shooting and reduced the crop yield. PBZ also influenced significantly in the dry shoot, with lineal increase in the dry roots. The hybrid Jennifer showed higher rates of absolute growth, resulting in higher plants than AF 7631, but, with no differences between them, regarding to the stem diameter, to side shooting and crop yield. In the greenhouse, it was obtained higher plants with higher side shooting and higher yield than that observed in the open field. The cultivation environment didn't interfere in none of the appraised qualitative characteristics, for the hybrid AF 7631, while, for Jennifer there was significant effect of the cultivation environment on the contents of soluble solids and titratable acidity, not affecting, however, the maturation index. However of the cultivation... (Complete abstract click electronic access below) / Doutor
17

Síntese de 5-organoteluro-1H-1,2,3-triazóis-1,4-dissubstituídos, funcionalização via reação de acoplamento cruzado de Sonogashira e síntese one-pot de derivados do indol-3-glioxila e indol-3-glioxil-1,2,3-triazóis / Synthesis of 5-organoteluro-1,4-disubstituted-1H-1,2,3- triazoles, functionalization via Sonogashira cross-coupling reaction and synthesis one-pot of indole-3-glyoxyl derivatives and indole-3-glyoxyl triazoles

Stanley Nunes Siqueira Vasconcelos 27 September 2013 (has links)
No capítulo 1 apresentamos uma síntese eficiente de compostos 5-organoteluro-1H- 1,2,3-triazóis realizada via reação de cicloadição [3+2] entre azidas orgânicas e alquinos substituídos com organotelúrio. Além disso, os 5-organoteluro-1H-1,2,3-triazóis foram funcionalizados na posição 5 do anel triazólico por reação de acoplamento cruzado de Sonogashira. A regioquímica dos produtos de cicloadição foram descritas com base em experimentos de RMN, cálculos teóricos e cristalografia de raio-x. Apresentamos uma proposta mecanística para a cicloadição mediada por cobre, baseada em experimentos de espectrometria de massas de alta resolução. No capítulo 2, investigamos a eficiência de reações one-pot com indol, cloreto de oxalila e diferentes nucleófilos para obtermos derivados do indol-3-glioxila em condições adequadas. Do mesmo modo, envolvendo a adição de azidas orgânicas, levando à síntese de indol-3-glioxil-1,2,3-triazóis, os produtos foram obtidos com rendimentos que variaram de 59 a 85%. / In chapter 1 we present an efficient synthesis of 5-organotelluro-1H-1,2,3-triazole compounds that was accomplished via the [3+2]-cycloaddition reaction of organoazides and organotelluro alkynes. Additionally, 5-organotelluro-1H-1,2,3-triazoles were readily functionalized at the 5-position via the Sonogashira cross-coupling reaction, leading to highly functionalised triazoles. The regiochemistry of the products was assessed by bidimensional NMR experiments, theoretical calculations and x-ray crystallography. We presented a mechanistic proposal for the cycloaddition mediated by copper, based on high resolution mass spectrometry experiments. In chapter 2 we investigated a general and efficient reaction of indole with oxalyl chloride and nucleophiles providing indole-3-glyoxyl derivatives which has been developed in mild conditions. In the same fashion, the other reaction involved the addition of organic azides leading to the synthesis of indole-3-glyoxyl-1,2,3-triazoles, which proceeds smoothly generating the products in moderate to high yields.
18

[pt] EMPREGO DA REAÇÃO DE CICLOADIÇÃO 1,3-DIPOLAR CATALISADA POR COBRE PARA A OBTENÇÃO DE NOVOS 1,2,3-TRIAZÓIS COM AÇÃO ANTICÂNCER EM LINHAGENS DE GLIOBLASTOMA E ANTILEISHMANIAL IN VITRO / [en] USE OF THE COPPERCATALYZED 1,3-DIPOLAR CYCLOADDITION REACTION TO OBTAIN NEW 1,2,3- TRIAZOLES WITH ANTICANCER ACTION IN GLIOBLASTOMA AND ANTILEISHMANIAL LINES IN VITRO

VERÔNICA DINIZ DA SILVA 29 April 2020 (has links)
[pt] Diante da importância terapêutica dos 1,2,3-triazóis e da versatilidade da reação de cicloadição 1,3-dipolar de Huisgen catalisada por cobre (reação CuAAC), o presente trabalho propõe a síntese de novos 1,2,3-triazóis-1,4-dissubstituídos abordando-se o conceito de hibridização molecular que associa ao núcleo triazólico outros grupos farmacofóricos privilegiados. Os compostos sintetizados foram divididos em duas séries e avaliados quanto ao potencial anticâncer, antileishmanial e distúrbios do sistema do nervoso central. Para obtenção da primeira série de triazóis utilizou-se como precursores aril azidas preparadas a partir de anilinas e éter propargílicos obtidos a partir de fenóis. A etapa chave da reação de CuAAC levou a obtenção dos 1,2,3-triazóis-1,4-dissubstituídos com rendimentos entre 50 e 85 porcento. Os compostos obtidos foram avaliados em diferentes linhagens celulares de glioblastoma (GBM, U87), incluindo linhagens celulares humanas altamente resistentes como a GBM02, GBM95, onde os compostos 2,2- (4,4-((1,3-phenilenebis(oxi))bis(methileno))bis(1H-1,2,3-triazol-4,1diyl))dibenzaldeído e (E)-4-metil-N-(2-(4-(fenoximetil)-1H-1,2,3triazolil)benzilideno)benzenosulfonohidrazida foram os mais ativos, com IC50 de 28,7 e 30,3 uM, respectivamente. Também foram avaliados nas linhagens de câncer de pulmão e próstata (A549, 22Rv1), entretanto, os compostos analisados não apresentaram atividade frente a estas linhagens celulares. Para a síntese da segunda série de compostos híbridos, tais quais os a-hidroxi-1,2,3-triazóis e benzocromenostriazóis, utilizou-se como materiais de partida aril azidas, preparadas através de ácidos aril borônicos e álcoois propargílicos, preparados a partir de benzaldeídos comerciais. A reação CuAAC na presença de metóxido de sódio levou a obtenção dos novos a-hidroxi-1,2,3-triazóis com rendimentos entre 35 e 75 porcento. A partir dos a-hidroxi-1,2,3-triazóis obtidos, realizou-se a reação de ativação C-H catalisada por paládio para obtenção benzocromenos-triazóis com rendimentos entre 35 e 40 porcento. Esses compostos foram avaliados como inibidores do transportador de glicina (Gly T1), transportadores relacionados a distúrbios neurológicos, e o composto (2-bromofenil)(1-(4-bromofenil)-1H-1,2,3-triazol-4-il)metanol apresentou 42porcento de inibição e IC50 de 13 uM, sendo este o melhor resultado de toda a série. Os compostos obtidos foram avaliados quanto a atividade antileishmanial (L. amazonenses), sendo que os compostos 2,2-(4,4-((1,3- phenilenebis(oxi))bis(methileno))bis(1H-1,2,3-triazol-4,1diyl)) dibenzaldeído e (E)-4-metil-N-(2-(4-(fenoximetil)-1H-1,2,3triazolil)benzilideno) benzenosulfonohidrazida apresentaram os melhores resultados, com IC50 de 8,85 e 8,81 uM, respectivamente. Todos os compostos sintetizados foram caracterizados por técnicas de espectroscopia de ressonância magnética nuclear (RMN), infravermelho (IV) e espectrometria de massas (CG-MS). / [en] In view of the therapeutic importance of 1,2,3-triazoles and the versatility of the copper-catalyzed Huisgen 1,3-dipolar cycloaddition (CuAAC), the present work proposes the synthesis of new compounds containing 1,2,3-triazoles-1,4-disubstituted derivatives by addressing the concept of molecular hybridization to obtain various triazole-containing compounds associated with other privileged pharmacophoric groups. The compounds synthesized were divided into two series and evaluated for their anticancer potential, as antileishmanial and central nervous system disorders. In order to the first series of triazoles, aryl azides were prepared from commercial anilines and propargylic ethers were obtained from commercial phenols. The key step of the CuAAC reaction afforded of 1,2,3-triazoles-1,4-disubstituted 50 - 85 percent in yields. All compounds were evaluated in different glioblastoma cell lines (GBM), including highly resistant human cell lines such as GBM02, GBM95, in which compounds 2,2-(4,4-((1,3 henylenebis(oxy))bis(methylene))bis(1H-1,2,3-triazole-4,1-diyl))dibenzaldehyde and (E)-4-methyl-N-(2-(4-(phenoxymethyl)-1H-1,2,3-triazol-1-yl)benzylidene)benzenesulfonohydrazide were the most active, with IC50 of 28.7 and 30.3 uM, respectively. The triazole derivatives were also evaluated for the lung and prostate cancer strains (A549, 22Rv1), however, the compounds analyzed did not show activity in these cell lines. For the synthesis of the second series of hybrid compounds such as a-hydroxy-1,2,3-triazoles and benzochromenes-triazoles, aryl azides were prepared from aryl boronic acids and the propargylic alcohols from commercial benzaldehydes. The CuAAC reaction in the presence of sodium methoxide provided the novel a-hydroxy-1,2,3-triazoles in 35 and 75 percents yields. The a-hydroxy-1,2,3-triazoles, were aplied palladium-catalyzed intermolecular (C-O) cyclization reaction and provided benzocromenes-triazoles in 35-40 percent yields. These compounds were evaluated as inhibitors of glycine transporter (Gly T1), which are related to neurological disorders. Therefore, compound (2-bromophenyl) (1-(4-bromophenyl)-1H-1,2,3-triazol-4-yl)methanol showed the best result with 42 percent of inhibition and IC50 of 13 uM. All compounds were avaluated for antileishmanial activity (L. amazonenses), compounds 2,2-(4,4-((1,3-phenylenebis(oxy))bis(methylene))bis(1H-1,2,3-triazole-4,1-diyl))dibenzaldehyde and (E)-4-methyl-N-(2-(4-(phenoxymethyl)-1H-1,2,3-triazol-1-yl)benzylidene)benzenesulfonohydrazide presented the best results, with IC50 de 8,85 e 8,81 uM, respectively. All the compounds synthesized were characterized by nuclear magnetic resonance (NMR), infrared (FTIR) spectroscopy and mass spectrometry (GC-MS) techniques.
19

Mineral Surface-Mediated Transformation of Insensitive Munition Compounds

Khatiwada, Raju, Khatiwada, Raju January 2016 (has links)
Abiotic transformation of compounds in the natural environment by metal oxides plays a significant a role in contaminant fate and behavior in soil. The ability of birnessite, ferrihydrite and green rust to abiotically transform insensitive munitions compounds (IMCs) parent (2,4 dinitroanisole [DNAN] and 3-nitro-1,2,4-triazol-5-one [NTO]), and daughter products (2-methoxy-5-nitro aniline [MENA], 2,4-diaminoanisole [DAAN]of DNAN; and 5-amino-1, 2, 4-triazol-3-one [ATO] of NTO) was studied in batch reactors under strictly controlled pH and ionic strength. The objectives of the study were to (i) assess the abiotic transformation potential of soluble DNAN, MENA, DAAN, NTO and ATO by birnessite, ferrihydrite and green rust, and (ii) identify inorganic reaction products. The study was carried out at metal oxide solid to IMC solution ratios (SSR) of 0.15, 1.5 and 15 g kg⁻¹ for birnessite and ferrihydrite and 10 g kg⁻¹ for green rust. Aqueous samples were collected at time intervals between 0 to 3 days after the reaction initiation and analyzed using HPLC with UV detection. Results indicated that DNAN was resistant to oxidation by birnessite and ferrihydrite at given solid to solution ratios. MENA was susceptible to rapid oxidation by birnessite (first order rate constant, 𝑘=1.36 h⁻¹ at 15 g kg⁻¹ SSR). The nitro groups from MENA largely mineralized to nitrite (NO₂⁻). In contrast, ferrihydrite did not oxidize MENA. DAAN was susceptible to oxidation by both birnessite and ferrihydrite, but about a six times higher oxidation rate was observed with birnessite (𝑘=1.18 h⁻¹) as compared to ferrihydrite (𝑘=0.22 h⁻¹) at an SSR of 1.5 g kg⁻¹. There was a complete loss of DAAN from solution after 5 min with birnessite at an SSR 15 g kg⁻¹ (𝑘≥90.5 h⁻¹). CO₂ evolution experiments indicate mineralization of 15 and 12 % of carbon associated with MENA and DAAN, respectively; under aerobic conditions with birnessite at an SSR of 15 g kg⁻¹. NTO was resistant to oxidation by birnessite and ferrihydrite at any SSR; however, there was slight initial loss from solution upon reaction with ferrihydrite at 0.15 and 1.5 g kg⁻¹ SSR and complete loss at 15 g kg⁻¹ SSR due to adsorption. ATO was susceptible to oxidation by birnessite and sorption by ferrihydrite. The first order rate constants (𝑘) for ATO with birnessite at 0.15 and 1.5 g kg⁻¹ SSR are 0.04 and 3.03 h⁻¹ respectively. There was complete loss of ATO from solution with birnessite at 15 g kg⁻¹ SSR (𝑘 ≥ 90.2 h⁻¹) within 5 min of reaction. Transformation products analysis revealed urea, CO₂ and N₂ as major reaction products with 44 % urea recovery and recovery of 51.5 % of ATO carbon as CO₂ and 47.8 % of ATO nitrogen as N₂ at 15 g kg⁻¹ SSR. The oxidation of ATO in the presence of birnessite was found to be independent of dissolved O₂. The results indicate that ATO, the major reductive (bio)transformation product of NTO, is readily oxidized by birnessite in soil. NTO was found strongly sorbed to ferrihydrite as compared to that of ATO. The results of the green rust experiment indicate rapid abiotic reduction of parent compounds NTO and DNAN to their reduced aminated daughter products. NTO was generally reductively transformed to 5-amino-1, 2, 4-triazol-3-one (ATO) within 10 min and completely reacted in 20 min. DNAN was rapidly transformed to its reduced daughter products MENA and 4-methoxy-5-nitroaniline (iMENA). The reduction occurred with a distinctive, staggered regioselectivity. Over the first 10 min, the para-nitro group of DNAN was selectively reduced, generating iMENA. Thereafter the ortho-nitro group was preferentially reduced, generating MENA. Both iMENA and MENA were subsequently transformed to the final reduction product DAAN within 1 day. X-ray absorption near edge spectroscopy data suggested oxidative transformation of green rust to lepidocrocite-like mineral forms, accounting for 94 % of the mineral products in the case of NTO reaction as compared to 62 % in the case of DNAN. The results taken as whole suggest that complete abiotic transformation of IMCs could be achieved by coupled stepwise green rust and birnessite treatments.
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Aplicação de diazocetonas como blocos de construção na síntese de n-heterociclos monocíclicos e bicíclicos / Application of diazoketones as building blocks in the synthesis of monocyclic and bicyclic n-heterocycles

Silva, João Victor Santiago da 12 April 2019 (has links)
O trabalho da tese apresentada é focado na aplicação de diazocetonas como intermediários avançados na síntese de sistemas N-heterocíclicos. No primeiro capítulo foi avaliada a reação de aza-Michael sobre as diazocetonas α,β-insaturadas, com o emprego de hidrazinas e hidroxilaminas como nucleófilos. Essa abordagem leva a formação de adutos de aza-Michael, que quando submetidos as reações de inserção N-H ou o rearranjo fotoquímico de Wolff, permitem o acesso aos núcleos de hexaidropiridazinas e 1,2-oxazinanas. Esses núcleos são encontrados em uma série de produtos naturais, apresentando diferentes tipos de atividades biológicas. Tendo isso em vista, foi planejada a aplicação da metodologia desenvolvida nesse capítulo na síntese da 1-(-)-Azafagomina e análogos. O capítulo 2 é focado na síntese de N-heterocíclos bicíclicos a partir de diazocetonas como blocos de construção, sendo esse capítulo foi dividido em duas partes. Na primeira parte foi avaliada à aplicação de diazocetonas α,β-insaturadas N-terminais na síntese de diferentes classes de núcleos N-heterocíclos, como as indolizidinas e pirrolizidinas. A estratégia sintética aplicada nesse tópico foi baseada na remoção de um grupo protetor de nitrogênio, a realização de uma reação de adição de aza-Michael intramolecular, e um rearranjo de Wolff fotoquímico para a construção da unidade bicíclica. Essa abordagem permitiu a obtenção de um escopo variado de núcleos indolizidínicos e pirrolizidínicos em bons rendimentos, e para alguns casos boa diastereosseletividade. A segunda parte desse capitulo teve como foco a síntese de núcleos [1,2,3]-triazólicos bicíclicos fundidos a partir de α-amino diazocetonas. A estratégia empregada para a construção da unidade bicíclica tem como etapa principal a formação in situ de um intermediário α-diazo imina, que via uma ciclização do tipo 5-endo-dig forma o núcleo triazólico bicíclico. A partir dessa abordagem foi possível a sintetizar um escopo variado de triazóis bicíclicos em bons rendimentos. / This work is focused on the application of diazoketones as advanced intermediates in the synthesis of N-heterocyclic systems. In the first chapter the aza-Michael reaction was evaluated on α,β-unsaturated diazoketones with the use of hydrazines and hydroxylamines as nucleophiles. This approach leads to the formation of aza-Michael adducts, which upon submission to the N-H insertion or the photochemical Wolff rearrangement, allows the access to hexahydropyridazine and 1,2-oxazinane cores. These units are found in a variety of natural products with different types of biological activities. Considering that we aimed the application of the developed methodology in the synthesis of the 1-(-)-Azafagomine and their analogues. The Chapter 2 is focused on the synthesis of bicyclic N-heterocyclic from diazoketones as building blocks. This chapter is divided in two parts. In the first part, the α,β-unsaturated N-terminal diazoketones were evaluated in the synthesis of different classes of N-heterocycles, such as indolizidines and pyrrolizidines. The methodology is based on the removal of a nitrogen protecting group, an intramolecular aza-Michael addition, and a photochemical Wolff rearrangement for the construction of the bicyclic unit. This approach not only allowed the synthesis of a broad scope of indolizidines and pyrrolizidines in good yields, but also good diastereoselectivity in some examples. The second part of this chapter was focused on the synthesis of bicyclic [1,2,3] triazolic cores from α-amino diazoketones. The strategy employed for the construction of the bicyclic unit is based on the in situ formation of a α-diazo imine intermediate, which upon a 5-endo-dig cyclization provide the bicyclic triazole core. The developed methodology allowed the synthesis of a varied scope of bicyclic triazoles in good yields.

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